This invention relates to a motor control center and is more particularly directed to a motor control center having individual control unit structures housing electrical control components that are modified periodically.
In industrial plants electrical power supplied to various equipment is generally controlled by control units which include components such as relays, circuit breakers, switches, motor starters, wiring, terminal blocks, etc. The control units for a given area of a plant are usually located in a single motor control center. The control units are stacked one on top of the other in separate control center sections which are then placed side by side. One advantage of motor control centers over other types of control equipment is their capability of being modified to accommodate changing requirements of the plant equipment. Additional components may be added to the control units after the motor control center is placed in service.
To facilitate wiring and servicing of the control units, the components are located in a saddle which may be easily removed from the motor control center after unlatching the control unit and disconnecting the electrical wiring. The size of each unit saddle or structure will depend on the number and type of the electrical devices desired in each of such units. The size, spacing and number of prepunched holes in each size of saddle may also vary to accommodate the different ratings of the electrical components, such as circuit breakers and motor starters. In the prior art the large number of possible combinations of sizes and ratings required that the saddle be made in many sizes and ratings to accommodate the extreme range of customer needs. It is desirable to provide a saddle that will accommodate a large number of different component groupings.
Additionally, after the motor control center is installed, the user may determine that additional electrical devices are required or that extra room for working with wiring is desired. In the prior art the customer could not modify the size of an existing unit saddle, but had to replace the existing unit saddle with a unit saddle that provided the necessary additional length.
It is an object of the present invention to provide a control center unit saddle that has a maximum flexibility for installation of the individual control units.
A further object of the present invention is to provide a unit saddle that can accommodate the installation of additional devices after the control center is in service.
Further objects and features of the invention will be readily apparent from the specification and appended drawings illustrating certain preferred embodiments.